1. Field of the Invention
The present invention relates to an inductor module, a silicon tuner module and a semiconductor device.
2. Description of the Related Art
In recent years, with the advent of organic electroluminescence (EL) television sets, extra-thin liquid crystal display (LCD) television sets and the like, there is a need for more reductions in the size and thickness of the tuner module, which is one of the largest functional parts in television receivers. In addition, increases in the number of functions such as incorporation of a recording function and a multi-window display mode have been being made, and there are an increasing number of cases where a plurality of tuner modules are mounted in a single television receiver. From this point of view, also, there has been a keener need for smaller-sized tuner modules.
To meet such a need as above, recently, there has been vigorous development of silicon tuner modules in which a television broadcast receiving function is realized by integrating an analog radio frequency (RF) circuit into a device based on a semiconductor such as silicon (Si) or silicon-germanium (SiGe).
Silicon tuner modules can be much reduced in volume, as compared with the so-called “CAN tuners,” which are box-type tuner modules in the related art. The large volume of CAN tuners arises from their configuration in which a large number of analog parts such as air-core coils, varactors and diodes with diameters of several millimeters constituting an analog part such as filter are mounted in a shielding metal, in addition to ICs (Integrated Circuit) such as mixer, PLL (Phase-Locked Loop) and the like. On the other hand, in silicon tuner modules, these analog parts are integrated into ICs to thereby realize reductions in size.
Meanwhile, in the case of integrating a filter function into an IC, the diameter of a coil which can be integrated in the IC is as small as several tens of micrometers. In this case, therefore, it is more difficult to enhance the performance of the filter than in the case of the CAN tuner. Specifically, with the filter function incorporated in an IC, it may be very difficult to sufficiently remove unwanted signals or to enhance reception sensitivity.
For solving this problem, a winding inductor (hereinafter referred to simply as “inductor”) functioning as a filter may be provided in the module, separately from the functions integrated in the IC, to thereby enhance the reception sensitivity.
It should be noted here, however, that if the inductor is an externally attached part, degradation of inductor characteristics may be caused thereby. The reason for this lies in that when an inductor as an externally attached part is mounted on the IC mounting substrate, the inductor has to be connected to the IC by laying around wire bonding, substrate wiring, or the like. In short, the parasitic resistance, parasitic capacitance, parasitic inductance and the like arising from the laying-around distances of the wiring and the like have adverse effects on the inductor characteristics.
Taking this into consideration, a configuration may be contemplated in which the inductor functioning as a filter is not provided as an externally attached part but is fabricated in the IC mounting substrate, so as to greatly shorten the laying-around distances of the wiring, etc. and thereby to restrain the degradation of inductor characteristics. Specifically, there have been proposals to incorporate an inductor element in a multilayer circuit board (refer to, for example, Japanese Patent Laid-open No. 2003-318549), to reduce noise, crosstalk or adverse effects of stray capacitances by a coil incorporated in the substrate (refer to, for example, Japanese Patent Laid-open No. 2005-347286), or to form a spiral inductor in the interposer in such a manner as to function as a filter (refer to, for example, Japanese Patent Laid-open No. 2008-004853).